<!-- 只用来写js中html的测试代码 -->
<div style="width: 100%;height: 100%;display: flex;flex-direction: column;">
    <div style="width: 100%;height: 70%;border: 5px dash black;" id="chat_div"></div>
    <div style="width: 100%;height: 30%;display: flex;">
        <textarea id="chat_input" cols="30" rows="10" style="width: 100%;"></textarea>
    </div>
    <div style="height: 0;"></div>
</div>